1. Field of the invention
The present invention relates to a battery powered pump, and more particularly to a battery powered pump in which means are provided for forcing fluid in the pumping chamber to flow in one direction and creating a negative pressure on the motorshaft bearing section.
2. Description of the prior art
The development in recent years of nickel-cadmium batteries with extremely low internal resistance and capable of delivering discharge current on the order of several amperes and also of quick charging in several minutes or not much longer than ten minutes has substantially expanded the field of battery powered devices. To take advantage of the situation, small and low-cost battery powered pumps are desirable for use with such devices as simplified water fountain equipment, hand or wall showers, bottle washers, water pistols, etc.
However, to manufacture this type of pump, it is necessary to make the battery chamber and the motor chamber watertight by packing the bearing of the motor shaft which drives vanes in the pump chamber. This packing necessarily means a considerable load on the motor and consumption of the battery power high enough to spoil the economy of a commercial article. Also, where vanes pump out fluid, the closer the vanes are to the motor bearing, the smaller will be the vane driving torque and the battery consumption. However, the flow of fluid is partly directed toward the motor shaft bearing and, therefore, a tighter packing around the bearing will be required with a resultant higher battery consumption.